Author Topic: Test run on Cloudcar Prop, new heads, exhaust and intake  (Read 2479 times)

Schmleff

  • Administrator
  • registered
  • *
  • Join Date: Jan 2006
  • Posts: 2573
  • My Gallery
  • I like Ninjas and Cake
  • Engine: VW 2110cc
  • Sonerai Model: Sonerai I
I wish all the guys talking about propellors would stop talking about "cavitation".  Cavitation only happens in a liquid.  Webster's definition is "the rapid formation and collapse of vapor pockets in a flowing LIQUID in regions of very low pressure."  Unless your prop is on a boat, and under water, it can't cavitate.  It can operate in a stalled condition, which high pitch props will due at very low forward speeds, but it can't cavitate.  OK?
:-*

I have three videos of three different low passes. Each one has a different prop and each sounds different. I will spice them together and post them. You can hear the 60" "beating the air".
« Last Edit: Jun 05, 2011 by Schmleff »
Jeff Lange
Sonerai I
N1463J

Buy the best and cry once - Gene Berg

Schmleff

  • Administrator
  • registered
  • *
  • Join Date: Jan 2006
  • Posts: 2573
  • My Gallery
  • I like Ninjas and Cake
  • Engine: VW 2110cc
  • Sonerai Model: Sonerai I
Ok, here is the video.

First the Prince 48x50 (tip speed 915fps)

Second the Cloudcars 52x60 (tip speed 998fps, likely transsonic)

Third the Cloudcars 52.5x56 (tip speed 824fps)

All of these passes are around the mid 190's. Its hard to tell the difference between the exhaust noise and prop noise at first. Listen to how much louder the second prop is.

The Prince and the 52x60 are louder. The last prop is much quieter and the exhaust noise is very distinct. I am not offering definitive answers as to why, but here is a difference between the three.

[yt=425,350]http://www.youtube.com/watch?v=ckzObR8BwqM[/yt]


« Last Edit: Jun 05, 2011 by Schmleff »
Jeff Lange
Sonerai I
N1463J

Buy the best and cry once - Gene Berg

thomefran

  • registered
  • Join Date: Oct 2010
  • Posts: 488
  • My Gallery
You can hear the difference.  Why is last one quieter.
Thom Francis
Sonerai II LT
N42HL

Regret is valid only when you are too old to correct it.

Schmleff

  • Administrator
  • registered
  • *
  • Join Date: Jan 2006
  • Posts: 2573
  • My Gallery
  • I like Ninjas and Cake
  • Engine: VW 2110cc
  • Sonerai Model: Sonerai I
I "think" because the Prince has to much area at the tip. The 52x60 does not have enough blade area for my drag profile and its over speeding the tips.

I am not sure. I am in data gathering mode.
Jeff Lange
Sonerai I
N1463J

Buy the best and cry once - Gene Berg

n3480h

  • Subscriber
  • registered
  • *
  • Join Date: Apr 2009
  • Posts: 1464
  • My Gallery
  • Engine: VW 2287cc
  • Sonerai Model: 2LS
Oh baby!  Number three gets my vote, lol.  Sounds extremely powerful.  How can I send this clip to my son?  He should hear what a good VW sounds like.

Tom

PS. found the link.
« Last Edit: Jun 06, 2011 by n3480h »
Member, Taildragging Stick Monkey Association

Schmleff

  • Administrator
  • registered
  • *
  • Join Date: Jan 2006
  • Posts: 2573
  • My Gallery
  • I like Ninjas and Cake
  • Engine: VW 2110cc
  • Sonerai Model: Sonerai I
Its on Youtube, just click on their logo and copy the link.

So far, #3 is the best prop for the plane. I have one more test prop coming and then Jay is going to cut me another one based on what we learn.  ;D
Jeff Lange
Sonerai I
N1463J

Buy the best and cry once - Gene Berg

N127PZ

  • Subscriber
  • registered
  • *
  • Join Date: Jan 2006
  • Posts: 2099
  • My Gallery
  • Engine: Revmaster 1700
  • Sonerai Model: SIIL
Wow....very cool sounds like P-51 on the attack !
Prayer does not use up artificial energy, doesn't burn up any fossil fuel, doesn't pollute. Neither does song, neither does love, neither does the dance.
Margaret Mead

 

Recent Topics

Angle of Incidence by Pttim
Today at 11:51 AM

IILS Main Gear Attachment by pilotsailing
Oct 29, 2014

I have to put the Sonerai 2 low wing up for sale. by 964SS
Oct 29, 2014

Engine Case Needed by vothsr
Oct 28, 2014

Tow Bar Attachment Questions... by PilotmanRB
Oct 27, 2014

Sonerai II Midwing for sale by planegene
Oct 27, 2014

On Bending IIS Sides by pilotsailing
Oct 26, 2014

Sonerai Radio Show During Oshkosh by dcstrng
Oct 26, 2014

Stretch -- I have to askā€¦ by dcstrng
Oct 25, 2014

Elevator trim...Anyone? by Pttim
Oct 25, 2014

Aileron Balance Weights by Bil438
Oct 24, 2014

Incomplete plans, parts list? by eschrom
Oct 24, 2014

New owner/Builder by Pttim
Oct 22, 2014

Sonerai Plans and Parts Announcement by PilotmanRB
Oct 22, 2014

Powered by EzPortal